uniform float v_time;

void main()
{
    float fR = 0.9*sin(0.0+ v_time*0.05) + 1.0;
    float fG = 0.9*cos(0.33+ v_time*0.05) + 1.0;
    float fB = 0.9*sin(0.67+ v_time*0.05) + 1.0;

    gl_FragColor=vec4(fR/2.0, fG/2.0, fB/2.0, 1.0);

}